astronomy

NGC 5665

NGC 5665 is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand NGC 5665 rather than just read about it. In short: NGC 5665 is a spiral galaxy in the northern constellation of Boötes. It was discovered on January 30, 1784 by German-British astronomer William Herschel.

Key takeaways

NGC 5665 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NGC 5665 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 5665 from memory before moving on to harder problems.

Reference excerpt

NGC 5665 is a spiral galaxy in the northern constellation of Boötes. It was discovered on January 30, 1784 by German-British astronomer William Herschel. This galaxy is located at a distance of 53.6 ± 7.7 million light-years (16.44 ± 2.37 Mpc), and is receding with a heliocentric radial velocity of 2,237 km/s. It is cataloged in Halton Arp's Atlas of Peculiar Galaxies as object number 49.

The morphological classification of NGC 5665 is unclear and differs by author. In the De Vaucouleurs system it was classified as SAB(rs)c pec?, which indicates a weakly-barred spiral galaxy (SAB) with a transitional inner ring structure (rs), loosely wound spiral arms (c), and suspected peculiarities (pec?). The galactic plane is inclined at an angle of 53°±5° to the plane of the sky, with the major axis aligned along a position angle of 145°. Evidence suggests that NGC 5665 underwent a gravitational interaction with another galaxy some 500 million years ago, swallowing a smaller companion. It is somewhat asymmetrical in appearance, retaining a single main spiral arm and the remains of several others. The galaxy is rich in dust and gas with a small bar at the center. There are numerous sites of star formation in the arm that match the age of the interaction. The spectrum of the core is a blend between a LINER and an H II region. NGC 5665 is part of the Virgo-Libra Cloud, which is part of the Virgo Supercluster.

References

External links Media related to NGC 5665 at Wikimedia Commons Image NGC 5665 Distance Archived 2011-06-07 at the Wayback Machine SIMBAD Data

Illustrations

Worked examples

Example 1 — a first encounter with NGC 5665

Start with the simplest possible case. Write down what NGC 5665 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to NGC 5665 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about NGC 5665 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of NGC 5665

In research: NGC 5665 appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses NGC 5665 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: NGC 5665 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arp objects, Boötes, Discoveries by William Herschel, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 5665 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study NGC 5665 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 5665 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain NGC 5665 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 5665 in simple terms?

NGC 5665 is a spiral galaxy in the northern constellation of Boötes. It was discovered on January 30, 1784 by German-British astronomer William Herschel.

Why does NGC 5665 matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study NGC 5665?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on NGC 5665.